CVE-2026-78439 Microsoft Office Graphics Component Remote Code Execution Vulnerability
An attacker can execute arbitrary code remotely via a stack-based buffer overflow in the Microsoft Office Graphics Component.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-78439?
CVE-2026-78439 is a high-severity memory corruption vulnerability in Microsoft Office 365 for Mac, published on 8 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Stack-based buffer overflow in Microsoft Graphics Component allows an unauthorized attacker to execute code over a network.
Weakness: CWE-121
Which versions are affected by CVE-2026-78439?
How do I fix CVE-2026-78439?
No fix has been published for CVE-2026-78439 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-78439 being exploited?
There is no known exploitation of CVE-2026-78439 in the wild and no public exploit code.
Sources
Also known as GHSA-6cw8-rp4c-jfpf.